/*
silverPDF is sponsored by Aleyant Systems (http://www.aleyant.com)

silverPDF is based on PdfSharp (http://www.pdfsharp.net) and iTextSharp (http://itextsharp.sourceforge.net)

Developers: Ai_boy (aka Oleksii Okhrymenko)

Permission is hereby granted, free of charge, to any person
obtaining a copy of this software and associated documentation
files (the "Software"), to deal in the Software without
restriction, including without limitation the rights to use,
copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the
Software is furnished to do so, subject to the following
conditions:

The above information and this permission notice shall be
included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR SPONSORS
BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
OTHER DEALINGS IN THE SOFTWARE.

*/
#region PDFsharp - A .NET library for processing PDF
//
// Authors:
//   Stefan Lange (mailto:Stefan.Lange@pdfsharp.com)
//
// Copyright (c) 2005-2008 empira Software GmbH, Cologne (Germany)
//
// http://www.pdfsharp.com
// http://sourceforge.net/projects/pdfsharp
//
// Permission is hereby granted, free of charge, to any person obtaining a
// copy of this software and associated documentation files (the "Software"),
// to deal in the Software without restriction, including without limitation
// the rights to use, copy, modify, merge, publish, distribute, sublicense,
// and/or sell copies of the Software, and to permit persons to whom the
// Software is furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included
// in all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
// THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER 
// DEALINGS IN THE SOFTWARE.
#endregion

using System;
using System.Diagnostics;
using System.Collections;
using System.Text;
using System.IO;
using PdfSharp.Drawing;
using PdfSharp.Drawing.Pdf;
using PdfSharp.Pdf;
using PdfSharp.Pdf.Internal;
using PdfSharp.Pdf.Filters;
using PdfSharp.Pdf.IO;

namespace PdfSharp.Pdf.Advanced
{
  /// <summary>
  /// Represents the content of a page. PDFsharp supports only one content stream per page.
  /// If an imported page has an array of content streams, the streams are concatenated to
  /// one single stream.
  /// </summary>
  public sealed class PdfContent : PdfDictionary
  {
    /// <summary>
    /// Initializes a new instance of the <see cref="PdfContent"/> class.
    /// </summary>
    public PdfContent(PdfDocument document)
      : base(document)
    {
    }

    /// <summary>
    /// Initializes a new instance of the <see cref="PdfContent"/> class.
    /// </summary>
    internal PdfContent(PdfPage page)
      : base(page != null ? page.Owner : null)
    {
      //this.pageContent = new PageContent(page);
    }

    /// <summary>
    /// Initializes a new instance of the <see cref="PdfContent"/> class.
    /// </summary>
    /// <param name="dict">The dict.</param>
    public PdfContent(PdfDictionary dict) // HACK
      : base(dict)
    {
      // A PdfContent dictionary is always unfiltered.
      Decode();
    }

    /// <summary>
    /// Sets a value indicating whether the content is compressed with the ZIP algorithm.
    /// </summary>
    public bool Compressed
    {
      set
      {
        if (value)
        {
          PdfItem filter = Elements["/Filter"];
          if (filter == null)
          {
            byte[] bytes = Filtering.FlateDecode.Encode(Stream.Value);
            Stream.Value = bytes;
            Elements.SetInteger("/Length", Stream.Length);
            Elements.SetName("/Filter", "/FlateDecode");
          }
        }
      }
    }

    /// <summary>
    /// Unfilters the stream.
    /// </summary>
    void Decode()
    {
      if (Stream != null && Stream.Value != null)
      {
        PdfItem item = Elements["/Filter"];
        if (item != null)
        {
          byte[] bytes = Filtering.Decode(Stream.Value, item);
          if (bytes != null)
          {
            Stream.Value = bytes;
            Elements.Remove("/Filter");
            Elements.SetInteger("/Length", Stream.Length);
          }
        }
      }
    }

    /// <summary>
    /// Surround content with q/Q operations if necessary.
    /// </summary>
    internal void PreserveGraphicsState()
    {
      // If a conent stream is touched by PDFsharp it is typically because graphical operations are
      // prepended or appended. Some nasty PDF tools does not preserve the graphical state correctly.
      // Therefore we try to relieve the problem by surrounding the content stream with push/restore 
      // graphic state operation.
      if (this.Stream != null)
      {
        byte[] value = Stream.Value;
        int length = value.Length;
        if (length != 0 && ((value[0] != (byte)'q' || value[1] != (byte)'\n')))
        {
          byte[] newValue = new byte[length + 2 + 3];
          newValue[0] = (byte)'q';
          newValue[1] = (byte)'\n';
          Array.Copy(value, 0, newValue, 2, length);
          newValue[length + 2] = (byte)' ';
          newValue[length + 3] = (byte)'Q';
          newValue[length + 4] = (byte)'\n';
          Stream.Value = newValue;
          Elements.SetInteger("/Length", Stream.Length);
        }
      }
    }

    internal override void WriteObject(PdfWriter writer)
    {
      if (this.pdfRenderer != null)
      {
        // GetContent also disposes the underlying XGraphics object, if one exists
        //Stream = new PdfStream(PdfEncoders.RawEncoding.GetBytes(this.pdfRenderer.GetContent()), this);
        this.pdfRenderer.Close();
        Debug.Assert(this.pdfRenderer == null);
      }

      if (Stream != null)
      {
        if (this.Owner.Options.CompressContentStreams)
        {
          Stream.Value = Filtering.FlateDecode.Encode(Stream.Value);
          Elements["/Filter"] = new PdfName("/FlateDecode");
        }
        Elements.SetInteger("/Length", Stream.Length);
      }

      base.WriteObject(writer);
    }

    internal XGraphicsPdfRenderer pdfRenderer;

    /// <summary>
    /// Predefined keys of this dictionary.
    /// </summary>
    internal sealed class Keys : PdfDictionary.PdfStream.Keys
    {
      /// <summary>
      /// Gets the KeysMeta for these keys.
      /// </summary>
      public static DictionaryMeta Meta
      {
        get
        {
          if (Keys.meta == null)
            Keys.meta = CreateMeta(typeof(Keys));
          return Keys.meta;
        }
      }
      static DictionaryMeta meta;
    }

    /// <summary>
    /// Gets the KeysMeta of this dictionary type.
    /// </summary>
    internal override DictionaryMeta Meta
    {
      get { return Keys.Meta; }
    }
  }
}